Adjustable propeller



May 3, 1932. w. WISK ADJUSTABLE PROPELLER Original Filed April 3, 1929 2Sheets-Sheet May 3, w. w s

ADJUSTABLE PROPELLER 2 Sheets-Sheet Original Filed April 3, 1929Final!!! Patented May 3, 1932 UNITED STATES WALTER WISK, OF NEW BRITAIN,CONNECTICUT ADJUSTABLE PROPELLER Application filed April 3, 1929, SerialNo. 352,255. Renewed September 28, 1931.

erator at will, yet former devices of this type have had manydisadvantages. In all of these devices there have been heretoforemembers extending out from the body of the device and in front of thepropeller. These members are subjected at all times to the danger ofbeing struck by flying objects and are bulky and unsightly.

The object of this invention is to provide 1 a new and improved meansfor accomplishing this purpose. The whole device is simple and compact,and is centered around the shaft which carries the propeller in aposition to the rear of the propeller. In this way the whole may beenclosed in the fuselage of the plane and is thus completely protectedfrom flying objects and from exposure to weather conditions. Thecompactness of the device also makes it stronger and less apt to getout' of order.

The invention accomplishes its objects in a new and improved mannerunknown in former devices of this kind.

In the past, propellers have ordinarily been made insuoh a manner thatthe pitch of the 5 blades is the same under all conditions. However,there are many disadvantages to such constructions. For instance, whenthe air pressure on the blades is suddenly increased, as when the planeturns into a strongwind,

40 the load on the motor is greatly increased. These great variations inload affect unfavorably the action of the motor and decrease both itswearing. qualities and its efficiency. If this change of load can beavoided, the life of the motor will be increased "and its operation willbe surer and smoother. Yet this must be accomplished withoutdisconnecting the shaft/on which the propeller is mounted from themotor. Also, the pitch of the blades must be changed automatically, soas not to de-- automatic adjusting means.

The invention consists of blades mounted so that they can be turned tovary the pitch. A spring pressed collar is so connectedto the bladesthat it tends to increase the pitch of the blades, while the bladesthemselves are unbalanced, that is, the surface upon one side of theaxis is greater than on the other side. 55

Thus air pressure on the blades tends to turn them to a point of lowerpitch, while the spring tends to turn them to a point of higher )itch.In addition, means are provided for adjusting the tension of the springso as to 7 increase or: decrease the pitch of the blades under the samepressure.

Further objects of my invention, and the invention itself, will becomeapparent from a study of the following description when taken inconnection with the accompanying drawings which form a part of thisapplicationJ In the drawings Fig. 1' is a top plan view of the device.

Fig. 2 is a cross-section on. the line 22 of Fig. l.

Fig. 3 is a cross-section on the line 33 of Fig. 1. j

'Fig. 4 is a cross-section on the line 44 of 35 Fig. 1.

' Fig. 5

is cross-section of the locking .means',

Referring to the various figures of the peller, mounted for turning inthe-sockets 4 on the housing 6. The base portions of-the blades arecylindrical, and fit intobores in the sockets 4: and are thusrotatablein the sockets. The bores extend slightly into the housing 6 asshown. The blades are un-' balanced, that is, the surface upon one sideof the axis of the cylindrical base portions is larger than on the otherside. As the blades are unbalanced on the same side, it is clear 1 0that air pressure will tend to turn the blades in opposite directions inthe sockets 4. To prevent longitudinal movement of the blades I- providecircumferential grooves 8 in the base portions of the blades and setscrews 10 -passing through threaded apertures in the .tion isscrew-threaded. The housing 6 has a square aperture therein which fitson the squared portion of the shaft and rests against shaft. A- nut 18is screwed on the threaded portion of the shaft and bears against thehousing 6 so as to hold it in place on the shaft.

Upon the intermediate portion of the shaft is a sleeve 20, slidablelongitudinally on the shaft but keyed to said shaft so as to rotatetherewith. A key 22 on shaft 12 extends through a slot 24 in sleeve 20and projects beyond the sleeve. Slidably mounted on the sleeve justbackof the housing 6 is a collar 26, which has a keyway 28 for theprojecting portion of the key 22. Thus the collar 26 is slidable. on thesleeve 20, which is in turn slidable on the shaft 12, yet all three willrotate together upon rotation of" the shaft. In

. the forward face of the collar 26 and in the rear face of the housing6 are'long narrow slots 30 and 32 in planes perpendicular to the axis ofthe blades. The slots in the housing pass just behind the bases of theblades connecting with the ends of the bores in which the blades aremounted. Links 34 moving in these slots connect the collar 26 totheblades 2 (see Fig. 2). These links are pivotally mounted in the slots30 in the collar by pins 36, and are pivoted at their other ends oneccentrically mounted pins 38 in the bases of the blades. These pins aremounted in different positions in the bases of the blades, one above thehorizontal plane through the, center of the bases, and the other belowthat plane, at points symmetrical with respect to the plane. Thus itwill be seen that movement of the collar 26 will turn the blades byerator from moving thesleeve by the to the sleeve and a part 44surrounding the part 42 and rotatable onthe part 42 by ball bearings 46.Thus while part 42 rotates with the sleeve and shaft, part 44 can remainstationary. The bearings are so arranged howinner part 42 of the collar40, so that the spring rotates with the shaft, sleeve and col- .lar 26.a shoulder 16 formed by the reducing of the Means 56 are provided forholding the sleeve 39 in the position to which it is adjusted by thehandle 52 (see Fig. 5). This locking means consists of a tubulaiymember.presses upon the head of the memberto urge it into locking position.The other end of the spring rests against a cap member 66 screwed intothe end of the tubular member 58. This gives an impositive detent whichwill hold the sleeve 39 in any position to which it may be moved withoutpreventing the o handle 52.

The operation of the device is as follows: Vhen the motor is started andreaches a certain speed, the pressure on the blades of the propellerincreases, but as the surface on one side of the axis of the blade isgreater than the surface on the other side, the pressure is alsogreater, and the blade tends to turn in the socket. This is madepossible. by the use of the links'34, collar 26 and spring 54. As theblades tend to turn in opposite directions, both tend to move the collar26 backward or away from the housing 6. This movement is resisted bythespring 54, and when the forces on the blades and the force of thespring are in equilibrium there will be no movement of the blades andthe motor will run at a constant speed. Suppose now, however, the planeturns into a strong wind. In

.the old type of plane, the result would be a slowing down of the motordue to the increased resistance to the propeller.

In the present device, however, this in; creased resistance increasesthe-force on the blades and turns the blades to a position where thisforce and consequently the load on the motor will again be inequilibrium with the force of the spring 54. This will be donepractically instantaneously as the pressure increases and thus the speedof the motor remains almost constant. in load to which motors of thistype are generally subjected is thus avoided and the life and efiiciencyof the motor will be greatly invice thus gives the benefit of automaticadjustment depending on the load on the motor, and at the same timeallows some arbitrary adjustment to meet special conditions. Inaddition, the device is simple, strong, and cheaply manufactured. Thereare few parts which can get out of order. The whole mechanism is verycompact and is concentrated about the shaft of the propeller, so thatthe whole is enclosed within the fuselage of the plane. In this way anydanger of injury by flying objects is avoided.

While I have described one embodiment of my invention, I wish it to beunderstood that Various changes may be made therein Within the scope ofthe appended claims.

I claim: 1. In apropeller, a shaft, a plurality of blades mounted torotate with said shaft, the longitudinal axes of said blades being fixedrelative to said shaft, said-blades being adapted to be turned to alower pitch about their longitudinal axes by the pressure of airthereon, a collar movable longitudinally of said shaft, means forvarying the pitch of said blades upon movement of said collar, a secondcollar movable longitudinally of said shaft, a spring between saidcollars for urging said first named collar in a direction such as toincrease the pitch of the blades, and

- means for moving said second-named collar to vary the tension of saidspring.

2. In a propeller, a shaft, a housing fixedly mounted on said shaft,blocks on said housing having circular bores therethrough perpendicularto said shaft, blades having cylindrical bases, said bases being mountedin said bores and being adapted to turn therein, said blades beingunbalanced with respect to their longitudinal axes, slots in saidhousing perpendicular to the axis of said bores and meeting said bores,a sleeve slidably but nonrotatably mounted on said shaft, a collarslidably but non-r-otatably mounted on said sleeve, links pivoted tosaid collar, pins eccentrically mounted in the ends of the bases of theblades, said links moving in the slots in said housing and being pivotedto said pins, said pins being set on opposite sides of a horizontalplane through the axes of said bases, whereby movement of said collarwill The large changes turn said blades in opposite directions, a sec-0nd sleeve slidable on said shaft, a second collar fixed on saidsecond-named sleeve, a coil springbetween said collars surrounding saidsleeves and shaft.

3. In a propeller, a shaft, a housing fixedly mounted on said shaft,blocks on said housing having circular bores therethrough perpendicularto said shaft, blades having cylindrical bases, said bases being mountedin said bores and being adapted to turn therein, said blades beingunbalanced with respect to their longitudinal axes, slots in saidhousing perpendicular to the axis of said bores and meeting said bores,a sleeve slidably but nonrotatably mounted on said shaft, a' collarslidably but non-rotatably mounted on said sleeve, links pivoted to saidcollar, pins ec- -centrically mounted in the ends of the bases of theblades, said links moving in the slots in said housing and being pivotedto said pins, said pins being set on opposite sides of a horizontalplane through the axes of said bases, whereby movement of'said collarwill turn said blades in opposite directions,

. a second sleeve, slidable on said shaft, a second collar fixed onsaidsecond-named sleeve, a coil spring between said first andsecondnamed collars surrounding said sleeves and shaft, manuallyoperable means for moving said second-named sleeve, and means on saidsecond-named sleeve engaging said shaft to hold said sleeve impositivelyfrom movement with respect to said shaft.

at. In a propeller, a shaft, a housing fixedly mounted on said shaft,blocks on said housfiing having circular bores therethroughperpendicular to said shaft, blades having cylindrical bases, said basesbeing mounted in said bores and being adapted to turn therein, saidblades being unbalanced'with respect to their longitudinal axes, slotsin said housing perpendicular to the axis of said bores and meeting saidbores, a sleeve slidably but nonrotatably mounted on said shaft, acollar slidably but non-rotatably mounted on said sleeve, links pivotedto said collar, pins eocentrically mounted in the ends of the bases ofthe blades, said links moving in the slots in said housing and beingpivoted to said pins, said pins being set on opposite sides of ahorizontal plane through the axes of said bases, whereby movement ofsaid collar will turn said blades in opposite directions, a secondsleeve slidable on said shaft, a second collar fixed on saidsecond-named sleeve, a coil spring between said first and secondnamedcollars surrounding said sleeves and shaft, a cylindrical memberrgtatably but non-slidably mounted on said second named collar, saidmember having a peripheral groove therein, a bifurcated member havingforks thereon, said forks engaging said groove, manually operable meansfor moving said bifurcated member to move said secondnamed sleeve, andmeans on said secondnamed sleeve engaging said shaft to hold said sleeveimpositively from movement with respect to the shaft.

In testimony whereof, I have hereunto set m si ature.

y gn WALTER WISK.

